[GROOVY-10343] STC fails to infer dependent type variable

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 3.0.11, 4.0.3
• Component/s: Static Type Checker
• Assignee: Eric Milles
• Reporter: Thodoris Sotiropoulos
• Created: 03/Nov/21 15:59
• Updated: 24/Jul/22 12:16
• Resolved: 16/May/22 17:17

Description

I have the following program

class A<T1, T2 extends T1> {
  T1 f;

  A(T1 f) {
    this.f = f;
  }
  T2 foo() { return null; }
}

class Test {
  void test() {
    Integer x = 1;
    var y = new A<>(x).foo();
    Integer z = y;
  }
  
}

Actual behavior

org.codehaus.groovy.control.MultipleCompilationErrorsException: startup failed:
test.groovy: 14: [Static type checking] - Cannot assign value of type java.lang.Object to variable of type java.lang.Integer
 @ line 14, column 17.
       Integer z = y;
                   ^

1 error

Expected behaviour

Compile successfully

Note that the program above compiles as expected in javac.

Tested against master (https://github.com/apache/groovy/commit/cee45d768bb65d1254a61a6dd4ce3c6a1f2ee3ca)